Go to Matching cell, then next empty cell in the row

[misty_trevino]

I have to track how much fuel some of the units in our fleet use and I inherited a clunky excel workbook to do this in. I was able to do the basic SUM functions and pull the totals into a worksheet to show the summary numbers, but that is about the limit of my knowledge.  I am sure there is an easy way to do this and I hope someone out there can tell me in simple language. 
I have unit numbers in column A (79 rows) and need to enter each gallon total in a column to the right of the appropriate unit #.  I get a daily report to tell me what units have been filled, so I can have any number of entries, up to 31, for each unit (row).  I would like to have a cell formula to:  go to the unit # that I enter in the formula cell, then move to the right in that row, to the first empty column and allow me to enter the gallons. I have two complications:  the unit number I get may not appear on my list in column A; when this happens it would be best if the cursor just stays on the data entry cell.  Also, I have 12 sections (for months) that I would modify and apply it to.

I'd rather not mess with VBA. And I don't see any reason why it can't just keep a running total rather than a next cell entry for each added gallon, if that's easier.  Thanks for any help you can give.

[#2 · Accepted solution]

so first of all, cell formulas will not move the cursor and will not move data. Cell formulas only perform a calculation to be displayed in that cell (or range).
In your application I would recommend numbering the days across (1-31) and enter the data in THAT corresponding day instead of using the next open cell.
A) this will make it easier to enter your data (you just go down today's column and enter the data as needed
B) it makes it easier to check your work (you go down todays column to see if the numbers match up with todays data
C) it can help with auditing (e.g. you can look and see patterns of when different vehicles are getting gas
D) it can help prevent errors. What if someone accidently writes MV052 instead of MV025 and therefore you have 2 entries for MV052 that day. In your orig way you may just enter it 2x on that row (next cell, and then next cell) and not even realize. But if you have to enter it on TODAY's column you would see that you already entered a number on that day for that vehicle.

[#3]

@mtarler Thanks very much for the great suggestions. I think I will put those to good use. It will definitely help with checking my work and verifying the entries daily.